[net.lang.f77] dbx with f77

donn@utah-gr.UUCP (Donn Seeley) (10/05/85)

	From: torre@ur-helheim.UUCP (Fernando Torre)

	... [A]fter invoking dbx, running the program and stopping it
	somewhere, there's no way of resuming execution ( next, step or
	continue ).

For what it's worth, this bug is fixed in the 4.3 BSD dbx.  The problem
is that f77 programs catch SIGTRAP, and older dbxes didn't realize that
they shouldn't deliver SIGTRAP to the debuggee if the trap was caused
by hitting a breakpoint which dbx itself installed.  I don't remember
why delivery of SIGTRAP to the user program caused a hang, but in any
case it was (and is) not desirable.  A hack that seems to kluge over
the problem without any awful side effects is to modify the loop in
usr.lib/libF77/main.c so that f77 programs don't catch SIGTRAP...

	In addition, at a given breakpoint, only a few variables are
	active, and as a consequence the rest of them cannot be printed
	at all.  ...

Which variables are not printable?  If you're referring to the fact
that COMMON variables used to be inaccessible to dbx, this bug is fixed
in 4.3 (by changing the symbol table generated by f77).  If your bug
is different, I'd be interested in the details.

4.3 should be available any minute now,

Donn Seeley    University of Utah CS Dept    donn@utah-cs.arpa
40 46' 6"N 111 50' 34"W    (801) 581-5668    decvax!utah-cs!donn